2007 Volume 6 Issue 3 Pages 479-485
Fluctuations of flowering time and cut flower quality due to meteorological changes in temperature in the Tohoku region were investigated in summer-to-autumn flowering-type ‘Iwa-no-hakusen’ and autumn flowering-type ‘Jinba’ chrysanthemum. After long day treatment, plants were grown under natural day length and high and low temperature conditions in a temperature gradient chamber (TGC), in which the air temperature followed the natural outside temperature fluctuation. The experiments were carried out twice in different seasons; the dates of transfer to TGC were 8 July and 10 August for ‘Iwa-no-hakusen’, and 22 September and 13 October for ‘Jinba’. In ‘Iwa-no-hakusen’, the temperature greatly varied during transfer on 8 July, and the anthesis was delayed by the high temperature after flower budding. The days to anthesis in transfer on 10 August was decreased by the shorter photoperiod than that at transfer on 8 July. In ‘Jinba’, anthesis was delayed by low temperature in both experiments. The days to anthesis following transfer on 13 October were increased by the lower temperature before flower budding than that of transfer on 22 September. The percentages of disk florets in ‘Iwa-no-hakusen’ were increased by low temperature and short photoperiod, and the number of florets in ‘Jinba’ were decreased by low temperature. In conclusion, the fluctuation of August flowering time of ‘Iwa-no-hakusen’ is induced by fluctuation of temperature, and the low temperature induces the delay in autumn flowering-type ‘Jinba’ in the Tohoku region.
